Preparation of metal salts of phosphorus sulfide-hydrocarbon reaction products



PREPARATION- OF METAL SALTS 0F PHOS- PHORUS SULFIDE-I-IYDROCARBON REAC- TION PRODUCTS Albert R. Sabol and Robert E. Karll, Munster, 11161., assignors to Standard Oil Company, Chicago, Ill;, a corporation of Indiana No Drawing. Filed July 21, 1958, Ser. No. 749,609

11 Claims. (Cl. 260-139) The use of such materials in lubricant compositions is described in US. Patents Nos. 2,316,080 and 2,316,082, issued April 6, 1943, to Clarence M. Loane and James W. Gaynor. The specifications'of these patents disclose a neutralization of phosphorus sulfide-olefin polymer reaction products and phosphorus sulfide-hydrocarbon reaction products by treatment with various neutralizing agents at about 100 F.400 F. While, in general, no

ditficulty is encountered in neutralizing such reaction products in the manner heretofore practiced, it has been observed that when neutralizing such reaction products with an amount of basic metal compound which wouldresult in a basic composition having a metal to phosphorus weight ratio on the order of from 3 to about 10, difficulties are encountered by reason of poor filtration rates which reduce the yields and increase the manufacturing costs. As more and more fuels having high sulfur contents come into use, it becomes necessary to provide lubricants which are basic and serve even'more effectively as agents to neutralize acidic compounds and to act as detergents to disperse particles of carbon, resin and the It is well known'that increas-' like in the lubricating oil. ing the metal contents, and hence the basicity,.of an additive of the type described herein will effectively increase the ability of the oil to neutralize acids formed by the It is also known that the most' combustion of the fuel. economical way of increasing the metal content of a-lubri c'ating oil containing an additive of the type described herein is to increase the metal to phosphorusratio of the additive rather than to increase the total amount of additive in the oil to obtain the desired metal content level.

A method of increasing the metal to phosphorus ratio of the additive is to neutralize the hydrolyzed reaction product of the phosphorus sulfide and the hydrocarbon with a basic metal compound in the presence of water and a mixture of a low molecular weight alkanol at a temperature not higher than the reflux temperature of" the water-alkanol mixture. This method of' preparation is disclosed and claimed in U.S. 2,806,022 issued Septem her 10, 1957 to A. R. Sabol. While the method therein disclosed produces a product having an increased metal to phosphorus ratio, it has been noted that occasionally.

the product obtained does not have the desired clarity, i.e. is somewhat hazy.

It is an object of the present invention to provide: an additive for lubricating oil having a high metal'to phosphorus ratio and good clarity.

It is a further object to provide a method of moreefiiciently neutralizingre'action products of a phosphorus sulfide and a hydrocarbon with a basic metal compound. Still another object of the invention is to provide an improved method of increasing the utilization of a basic metal compound in the neutralization of reaction products of a phosphorus sulfide and a hydrocarbon. A more specific object is to provide a method of neutralizing the reaction product of a phosphorus sulfide and a hydrocarbon with a basic metal compound whereby a substantially clear product, readily filterable and having a high metal to phosphorus ratio is obtained. Other objects and advantages of the present invention will become apparent from the following description thereof.

In the prior method of neutralization as disclosed and taught in U.S. 2,806,022, supra, the hydrolyzed reaction product of a phosphorus sulfide and a hydrocarbon is neutralized with a basic compound in the range of from about 3 to about 15 parts, by weight, of metal per part of phosphorus, present in the phosphorus sulfide-hydrocarbon reaction product, in the presence of from about 0.5 to about 2', preferably 1, mol of water per mol of metal and from about 2 to about 20 mols of an alkanol, of 1' to 3 carbon atoms, per mol of the metal used in the neutralization. The neutralization is carried out at or below the reflux temperature of the mixture.

In accordance with the present invention, the above neutralization method is modified and improved to attain the foregoing objects by hydrolyzing the reaction product of the phosphorus sulfide and the hydrocarbon at a temperature of from about 300 F. to about 500 F., and sub je'cting the hydrolyzed product, prior to neutralization,

to a pretreating stage by heating with analkanol or with a water and alkanol mixture for from 0.25 to 5 hours, preferably about one-half hour under reflux temperature conditionsof the alkanol or water-alkanol mixture, adding an oil-slurry of the basic metal compound to the refluxed mixture, and heating the mixture under such re flux temperature conditions for about 1 to 5 hours, preferably about 3 hours. The temperature is then raised to about 350 F. to 450 F., preferably about 400 F., and the alcohol and water distilled off; the heated neutralized product may then, if desired, be filtered. The hydrolyzed phosphorus sulfide-hydrocarbon reaction product may be contacted with an adsorbent clay or otherwise treated before the pretreatment step to remove in organic phosphorus compounds and'low molecular weight organic phosphorus compounds. t

In the preparation of the phosphorus sulfide-hydrocarbon reaction product, the hydrocarbon is'reactedwith a phosphorus sulfide, such as P 5 P 8 P 8 or other phosphorus sulfides, and preferably phosphorus pentasulfide, P285.

The hydrocarbon constituent of this reaction is described in detail in US. 2,316,080, 2,316,082, and 2,316,- 088, each issued to Loane et a1; on April 6, 1943. Briefly,

the hydrocarbon constituents are preferably mono-olefinhydrocarbon polymers or mixtures of mono-olefin poly-' mers and iso-mono-olefin polymers having molecular weights ranging; from about m about 50,000, prefer ably from aboutSOOto about 10,000resulting' from the polymerization of low molecular weight: mono-olefinic hydrocarbons and/ or isomono-olefin'ichydrocarbons,such as propylenes, butylenes and amylenes, or the copolymers obtained by the polymerization of hydrocarbon mixtures containing iso-rnono-olefins and mono-olefins of'less' than 6 carbon atoms. The polymers maybe obtained by the polymerization of these olefins'or mixtures of olefins in the presence of acatalyst such as sulfuricacid, pho s phoric acid, boron fluoride, aluminum chlorid'e'or other similarhalide catalysts of the Friedel-Cra'fts type. A suitable polymer for the reaction witli'phosph'orus sulfide is the product obtained by polymerizing in the liquid phase a hydrocarbon mixture containing butylenes and isobutylenes together with butanes and some C and C hydrocarbons at a temperature between about 80 F. to about 100 F., in the presence of aluminum chloride.

Essentially paraflinic hydrocarbons such as bright stock residuums, lubricating oil distillates, petrolatums, or paraflin waxes, may be used. There can also be employed the condensation products of any of the foregoing hydrocarbons, usually through first halogenating the hydrocarbons, with aromatic hydrocarbons in the presence of anhydrous inorganic halides, such as aluminum chloride, zinc chloride, boron fluoride, and the like.

Other preferred olefins suitable for the preparation of the hereindescribed phosphorus sulfide reaction products are olefins having at least 20 carbon atoms in the molecule of which from about 13 carbon atoms to about 18 carbon atoms, and preferably at least 15 carbon atoms, are in a long chain. Such olefins can be obtained by the dehydrogenation of paraifins, such as by the cracking of parafiln Waxes or by the dehalogenation of alkyl halides, preferably long chain alkyl halides, particularly halogenated paraifin waxes.

Also contemplated within the scope of the present invention are the reaction products of a phosphorus sulfide with an aromatic hydrocarbon, such as for example, benzene, naphthalene, toluene, xylene, diphenyl and the like or with an alkylated aromatic hydrocarbon, such as for example, benzene having an alkyl substituent having at least four carbon atoms, and preferably at least eight carbon atoms, such as long chain paraffin wax.

In general, the preparation of the phosphorus sulfidehydrocarbon reaction product in accordance with the present invention is carried out in the following manner:

The hydrocarbon, such as for example, an olefinic polymer of the desired molecular weight, is reacted with from about 1% to about 50% and preferably from about 5% to about 25%, of a phosphorus sulfide, e.g., P S at a temperature of from about 200 F. to about 600 F. in a non-oxidizing atmosphere, such as for example, an atmosphere of nitrogen. The reaction is carried out for from about one to about ten hours or more, and preferably for about five hours. The phosphorous sulfide-hydrocarbon reaction can, if desired, be carried out in the presence of a sulfurizing agent as described in U.S. 2,316,087, issued to J. W. Gaynor and C. M. Loane, April 6, 1943. The reaction product obtained is then hydrolyzed at a temperature of from about 300 F. to about 500 F., and preferably at a temperature of 325 F. to 375 F., by a suitable means, such as for example, by introducing steam through the reaction mass. The hydrolyzed product containing inorganic phosphorus acids formed during the hydrolysis may then be contacted with an adsorbent material such as Attapulgus clay, fullers earth and the like at a temperature of from about 100 F. to about 500 F. as more fully described and claimed in U.S. 2,688,612, issued September 7, 1954, to Roger W. Watson, and the treated hydrolyzed product filtered to obtain a filtrate substantially free of inorganic phosphorus acids and low molecular weight organic phosphorus compounds.

' Prior to neutralization, the hydrolyzed reaction product, with or without clay treating and preferably diluted with a normally liquid hydrocarbon oil, generally the same as or similar to the oil in which the finished additive is to be used, is mixed with the alkanol or the alkanol-water mixture and heated under reflux temperature conditions of the alkanol or the water-alkanol mixture, for example at a temperature of from about 155 F. to about 160 F. for a water-methanol mixture for a period of from about 0.25 to about 5 hours. In the herein described invention from about 2 to about 20 mols of the alkanol and from about 0.5 to about 2 mols of water per mol of basic metal compound, to be used for the neutralization of the hydrolyzed material, are employed. If desired, a portion of the required alkanol or of the water and alkanol mixture can be used in the pre treating stage of the remaining portions used in the following neutralization step.

The pretreated heated mixture, cooled to a temperature of from about F. to about 140 F., preferably about R, if desired, is then neutralized with a basic metal compound; as noted above, in the presence of a portion of the alkanol and Water mixture, if desired. The neutralization step is carried out with a suitable basic metal compound such as a hydroxide, carbonate, oxide or sulfide of an alkaline earth metal or an alkali metal such as, for example, potassium hydroxide, sodium hydroxide, barium oxide, barium hydroxide, barium sulfide or the like. Other basic metal compounds may also be used such as, for example, lead oxide, mercuric oxide, or the like. It is preferable, however, to use an alkaline earth metal compound such as barium oxide.

The basic metal compound may be admixed directly with the phosphorus sulfide-hydrocarbon reaction product; it is preferable, however, to form a slurry of the basic metal compound in a normally liquid hydrocarbon of a type comparable to the lubricating oil in which the additive is to be used. The total amount of the basic metal compound present in the slurry should be from about 3 to about 15 parts per part of phosphorus present in the phosphorus sulfide-hydrocarbon reaction product which is to be neutralized therewith.

The optimum amount of water necessary is about 1 mol per mol of basic metal compound used in the neutralization, although as little as 0.5 mol of water or as much as 2 mol of water per mol of basic metal compound may be used. If an inadequate amount of Water is used in the neutralization step, the neutralized product tends to gel and thereby becomes diflicult to filter; too much water reduces barium utilization and, thus, Ba/P ratios are lower.

The alcohol used may be either methyl, ethyl or propyl alcohol, it is preferable, however, to use methyl alcohol. About 2 to about 20 mols of alcohol per mol of basic metal compound may be used although the preferred range is from about 5 to about 10 mols of alcohol per mol of basic metal compound used in the neutralization step.

If a portion of the water-alkanol mixture is used in the pretreating step and a portion used in the neutralization step, is preferred, but not essential, that equal proportions of the mixture be used in each of such steps; accordingly, when operating in this manner, from about 0.25 to about 1 mol of water and from about 1 to about 10 mols of the alkanol, per mol of basic metal compound can be suitably employed in each of the pretreating and neutralizing steps.

After admixing the ingredients as pointed out hereinbefore, the neutralization reaction is preferably carried out by heating the mixture to a temperature not higher than its reflux temperature for about 1 to about 5 hours. A reflux condenser is employed to condense any alcohol or water vapors which may be vaporized. The higher neutralization temperatures obtained at reflux cause the reaction to proceed at a faster rate and are therefore preferable to very low temperature neutralization. After a period of from about 1 to about 5 hours has elapsed, the temperature is increased to about 400 F. and the water and alcohol vapors are permitted to pass through the reflux condenser, and the product is then filtered through a filtering medium such as Celite or the like.

The improvement in clarity obtained by the method of the present invention is shown by the following examples given by way of illustration.

Example I A polybutene having a mean molecular weight of about 780 was reacted with 15.5% (wt) P 8 at about 450 F. for about 5.5 hours, the product hydrolyzed by steaming at- 300 F. for about 5.5 hours and the resultant hydrogive a product having a phosphorus content of 2.71% (eqv. to 1 mol phosphorus). product will be referred to as Product A.-

To a mixture, 1140 grams of Product A, and 500 grams of an SAE-5W motor oil base were added 245 grams This hydrolyzed reaction- BaO (1.60 mol) and the mixture stirred at about 75 F.

to obtain thorough mixing. To the mixture were then added 0.8 mol (23 grams) water per mol of BaO and 7" mols (360 grams) methanol per mol of BaO and the entire mixture heated under reflux conditions for 3 hours at 158-160 F. The refluxed mixture was then heated to about 400 F. to remove water and methanol and the neutralized product filtered through Celite. The recovered neutralized product was light brown in color and had a clarity value on the HKT scale of about 2.

The HKT scale is an arbitrary eight point scale for evaluating product clarity. On the scale a value of is opaque or hazy and a value of 7 is crystal clear; other values are 1-2 translucent, 3-4 transparent and 5-6 very clear.

Example 11 To a mixture of 1140 grams of Product A, supra (Example I) and 500 grams of an SAE 5W motor oil base were added 23 grams of water and 360 grams methanol and the mixture heated under reflux conditions at 160 F. for two hours. The amount of water and the amount of methanol employed were the equivalent of 0.8 mol and 7 mols respectively per mol of barium oxide to be used in the subsequent neutralization step.

After 2 hours reflux pretreatment, the mixture was cooled to 130 F. and 245 grams (1.6 mol) barium oxide added and the mixture refluxed at 155160 F. for an additional 2 hours. The temperature of the refluxed neutralized mixture was then raised to about 400 F the water and methanol removed and the product filtered through Celite. The recovered neutralized product was dark red in color and had a clarity value on the HKT scale of 6-7.

While we do not wish to be held to any theoretical consideration for the eifectiveness of our herein described invention, it is believed that when the hydrolyzed phosphorus sulfide-hydrocarbon reaction product is neutralized with the basic metal compound, a diflicult-to-filter metal sulfide may be formed. However, when the hydrolyzed product is first refluxed with the water-alkanol mixture, the loosely-bound sulfur is stabilized, possibly as a thioester, and less metal sulfide is formed in the subsequent neutralization.

The product obtained in accordance with the herein described invention are useful as additives in lubricant compositions, particularly for use in the lubrication of internal combustion engines.

Percentages given herein and in the appended claims are weight percentages unless otherwise stated.

While we have described our invention by reference to specific embodiments thereof, the same are given by way of illustration only and are not intended to limit the breadth of the invention, but includes Within its scope such modifications and variations as come within the spirit of the appended claims.

We claim:

1. In the preparation of a metal-containing neutralized reaction product of a phosphorus sulfide and a hydrocarbon in which the hydrocarbon is reacted with from about 1% to about 50% of a phosphorus sulfide at a temperature of from about 200 F. to about 600 F., the resultant reaction product hydrolyzed at a temperature of from about 300 F. to about 500 F. and the hydrolyzed reaction product neutralized with a basic metal compound, the improvement comprising refluxing the hydrolyzed reaction product, prior to neutralization, with at least a portion of a mixture of from 0.5 to about 2 mols of water per mol of said basic metal compound and from about Ztoabout 20 mols of an alkanol,, of fromv 1 to about 3.

carbon atoms, per,- mol of said basic metal compound, at

the reflux temperature of said water-alkanol. mixture for-' a period of from about 0.25 hourto about 5 hours, neu-, tralizing: said refluxed hydrolyzed reaction product with said basic metalcompound in the presence of any unused portion of saidwater-alkanol mixture, heating the resultant neutralized product to a temperature above said reflux temperature and removing said water and said alkanol.

2.- In the preparation of a metalecontaining neutralized reaction product of a phosphorus sulfide and a hydrocarbon in which the hydrocarbon is reacted with from about 1% to about 50% of a phosphorus sulfide at a temperature of from about 200 F. to'about 600 F., the resultantreaction product hydrolyzed at a temperature of from about 300 F. to about 500 F., and the hydrolyzed reaction product neutralized with a basic metal corn pound, the improvement comprising refluxing the hydrolyzed reaction product, prior to neutralization, with a mixture of from 0.50 to about 2 mols of water per mol of saidbasic metal compound and from about 2 to about 20 mols of an alkanol, of from 1 to about 3 carbon atoms, per mol of said basic metal compound, at the reflux temperature of said water-alkanol mixture for a period of from about 0.25 hour to about 5 hours, neutralizing said refluxed hydrolyzed reaction product with said basic metal compound, heating the resultant neutralized product to a temperature above said reflux temperature and removing said water and said alkanol removed.

3. The method of claim 2 in which the neutralized product is heated to a temperature of about 400 F. to remove said water and said alkanol.

4-. The method of claim 2 in which said phosphorus sulfide isphosphorus pentasulfide and said hydrocarbon is a polybutene having a molecular Weight of from about to about 50,000.

5. The method of claim 2 in which the basic metal compound is barium oxide.

6. The method of claim 1 in Which the alkanol is methanol.

7. In the preparation of a metal-containing neutralized reaction product of phosphorus pentasulfide and a polybutene having a molecular Weight of about 150 to about 50,000 in which the polybutene is reacted with from about 1% to about 50% of phosphorus pentasulfide at a temperature of from about 200 F. to about 600 F., the resultant reaction product hydrolyzed at a temperature of from about 300 F. to about 500" F. and the hydrolyzed reaction product neutralized with from about 3 to about 15 parts, by weight, of barium oxide per part by weight of phosphorus in said phosphorus pentasulfidepolybutene reaction product, the improvement comprising refluxing the hydrolyzed reaction product, prior to neutralization, with a mixture of from 0.5 to about 2 mols of water per mol of said barium oxide and from about 2 to about 20 mols of an alkanol, of from 1 to about 2 carbon atoms, per mol of said barium oxide at the reflux temperature of said water-alkanol mixture for a period of from about 0.25 hour to about 5 hours, neutralizing said refluxed hydrolyzed reaction product with said barium oxide, heating the resultant neutralized prod net to a temperature above said reflux temperature, and removing said water and said alkanol.

8. In the preparation of a metal-containing neutralized reaction product of a phosphorus sulfide and a hydrocarbon in which the hydrocarbon is reacted with from about 1% to about 50% of a phosphorus sulfide at a temperature of from about 200 F. to about 600 F., the resultant reaction product hydrolyzed at a temperature of from about 300 F. to about 500 F., and the hydrolyzed reaction product diluted with a lubricating oil diluent to a phosphorus content of from about 0.5 to about 5%, nehtralized with from about 3 to about 15 parts, by weight, of a basic metal compound per part by weight of phos.

phorus in said phosphorus sulfide-hydrocarbon reaction product, the improvement comprising refluxing the diluted hydrolyzed reaction product, prior to neutralization, with a mixture of from 0.5 to about 2 mols of water per mol of said basic metal compound and from about 2 to about 20 mols of an alkanol, of from 1 to about 3 carbon atoms, per mol of said basic metal compound, at the reflux temperature of said water-alkanol mixture for a period of from about 0.25 hour to about 5 hours, neutralizing said refluxed hydrolyzed reaction product with said basic metal compound, heating the resultant neutralized product to a temperature above said reflux temperature and removing said water and said alkanol removed.

9. The method of claim 8 wherein the diluted hydrolyzed reaction product is contacted with an adsorbent clay at a temperature of from about 100 F. to about 500 F. prior to refluxing with said water-alkanol mixture.

10. In the preparation of a metal-containing neutralized reaction product of a phosphorus sulfide and a hydrocarbon in which the hydrocarbon is reacted with from about 1% to about 50% of a phosphorus sulfide at a temperature of from about 200 F. to about 600 F., the resultant reaction product hydrolyzed at a temperature of from about 300 F. to about 500 F., and the hydrolyzed reaction product neutralized with from about 3 to about 15 parts, by weight, of a basic metal compound per part by weight of phosphorus in said phosphorus-sulfide hydrocarbon reaction product, the improvement comprising refluxing the hydrolyzed reaction product, prior to neutralization, with a mixture of from 0.25 to about 1 mol of water per mol of said basic metal compound and from about 1 to about 10 mols of an alkanol, of from 1 to about 3 carbon atoms, per mol of said basic metal compound, at the reflux temperature of said water-alkanol mixture for a period of from about 0.25 hour to about 5 hours, neutralizing said refluxed hydrolyzed reaction product with said basic metal compound, in the presence of from about 0.25 to about'l mol additional water and from about 1 to about 10 mols additional said alkanol; and heating the resultant neutralized product to a temperature above said reflux tempertaure-and said water and said alkanol removed.

11. In the preparation of a metal-containing neutralized reaction product of a phosphorus sulfide and a hydrocarbon in which the hydrocarbon is reacted with from about 1% to about of a phosphorus sulfide at a temperature of from about 200 F. to about 600 F., the resultant reaction product hydrolyzed at a temperature of from about 300 F. to about 500 F., and the hydrolyzed reaction product neutralized with a basic metal compound, the improvement comprising heating the hydrolyzed reaction product, prior to neutralization, with from about 2 to about 20 mols of an alkanol, of from 1 to about 3 carbon atoms, per mol of said basic metal compound at the reflux temperature of said alkanol for a period of from about 025 hour to about 5 hours, neutralizing said refluxed hydrolyzed reaction product with said basic metal compound in the presence of from about 0.5 mol to about 2 mols of water per mol of said basic metal compound, heating the resultant neutralized product to a temperature above said reflux temperature and removing said water and said alkanol.

References Cited in the file of this patent UNITED STATES PATENTS 2,647,889 Watson et al Aug. 4, 1953 2,806,022 Sabol Sept. 10, 1957 

1. IN THE PREPARATION OF A METAL-CONTAINING NEUTRALIZED REACTION PRODUCT OF A PHOSPHORUS SULFIDE AND A HYDROCARBON IN WHICH THE HYDROCARBON IS REACTED WITH FROM ABOUT 1% TO ABOUT 50% OF A PHOSPHOROUS SULFIDE AT A TEMPERATURE OF FROM ABOUT 200*F. TO ABOUT 600*F., THE RESULTANT REACTION PRODUCT HYDROLYZED AT A TEMPERATURE OF FROM ABOUT 300*F. TO ABOUT 500*F. AND THE HYDROLYZED REACTION PRODUCT NEUTRALIZED WITH A BASIC METAL COMPOUND, THE IMPROVEMENT COMPRISING REFLUXING THE HYDROLYZED REACTION PRODUCT, PRIOR TO NEUTRALIZATION, WITH AT LEAST A PORTION OF A MIXTURE OF FROM 0.5 TO ABOUT 2 MOLS OF WATER PER MOL OF SAID BASIC METAL COMPOUND AND FROM ABOUT 2 TO ABOUT 20 MOLS OF AN ALKANOL, OF FROM 1 TO ABOUT 3 CARBON ATOMS, PER MOL OF SAID BASIC METAL COMPOUND, AT THE REFLUX TEMPERATURE OF SAID WATER-ALKANOL MIXTURE FOR A PERIOD OF FROM ABOUT 0.25 HOUR TO ABOUT 5 HOURS, NEUTRALIZING SAID REFLUXED HYDROLYZED REACTION PRODUCT WITH SAID BASIC METAL COMPOUND IN THE PRESENCE OF ANY UNUSED PORTION OF SAID WATER-ALKANOL MIXTURE, HEATING THE RESULTANT NEUTRALIZED PRODUCT TO A TEMPERATURE ABOVE SAID REFLUX TEMPERATURE AND REMOVING SAID WATER AND SAID ALKANOL. 